Among the semiconductor parts used in electronic devices, there are parts, such as CPU for computers and power semiconductors for power source control including inverters, converters, and the like, which generate heat during their use. In order to protect these semiconductor parts from the heat and to operate them normally, there is a method wherein the generated heat is conducted to heat-radiating parts such as a heat sink to radiate the heat. A thermal conductive compound is applied between these semiconductor parts and the heat-radiating parts so as to adhere them closely and is used so as to conduct the heat of these semiconductor parts to the heat-radiating parts efficiently. Recently, the performance of the electronic devices using these semiconductor parts has been improved and miniaturization and high-density mounting have been advanced, so that a higher thermal conductivity is required for the thermal conductive compound to be used for heat-radiation and it is also required for the compound to have a high consistency for a good coating workableness.
A thermal conductive compound is a grease-like composition wherein a filler having a high thermal conductivity, e.g., a metal oxide such as zinc oxide or aluminum oxide, an inorganic nitride such as boron nitride, silicon nitride, or aluminum nitride, a metal powder such as aluminum or copper, or the like, is dispersed in a base oil such as a liquid hydrocarbon, a silicone oil, or a fluorinated oil. For example, there are disclosed one wherein a specific thermal conductive inorganic filler is blended with a hydrocarbon oil and a fluorinated oil (Patent Document 1 etc.), one wherein aluminum nitride subjected to surface treatment with a specific organosilane is blended with a base oil such as a silicone oil (see Patent Document 2 etc.), one blended with a specific surface modifier (see Patent Documents 3, 4, etc.), and the like.
Patent Document 1: Japanese Patent No. 2938428
Patent Document 2: Japanese Patent No. 2930298
Patent Document 3: JP-A-2006-210437
Patent Document 4: JP-A-2006-96973